1. Field of the Invention
This invention generally relates to window latches. More specifically, it is concerned with window latches that can be quickly operated to open a window to allow fast, free egress through said window, especially in an emergency situation such as a fire. Windows that employ such latches will normally be located in the walls of a room. Such windows could, however, also be located in building roofs and thereby serving as skylights for lofts, attics and the like.
2. Discussion of the Background
Windows for emergency exit use are well known. For example, European Patent Application No. 0 329 315 A1 discloses a pivotally mounted window that, upon actuation of a control handle, releases a catch in order to disengage the lower ends of arms located in the vertical components of a window sash. Forces applied by gas driven springs then act upon the arms in such a manner that said arms move outwardly about a hinged axis in an upper horizontal component of the window sash and thereby forcing the window sash outward and clear of the window frame to create an emergency exit.
U.S. Pat. No. 5,056,262 discloses a window guard screen and frame assembly installed on the jamb of a building window in a manner that prevents unauthorized external access, but permits quick egress from within the building through the window in case of an emergency such as a fire. A screen can be fabricated from a metal sheet whose margins are folded inward to define channel-like ends and side branches bordering a planar field. The frame is dimensioned to overlie and nest within the window jamb to which the window is secured. Integral with the inner surface of the frame and bordering the opening therein is a slideway socket for receiving a screen. The socket is defined by end and side legs which complement the branches of the screen. Hinge pins are mounted on the end legs of the slideway socket adjacent to one of the side legs. These pins extend through elongated slots formed in corresponding end branches of the screen. The screen is slidable to an extent that is limited by the slots from a security mode position in which the screen is confined to the socket. The egress mode screen is free to swing on the hinge pins out from the frame opening and thereby permitting exit through the window. A releasable latch is mounted on the opposing side leg of the socket to engage a corresponding side branch of the screen to lock the socketed screen in its locked, security mode position. When released, the latch permits the screen, which is spring loaded, to slide to its fast egress permitting mode.
These prior art fast egress systems have latch systems that are activated by small levers located on the window sash. Such levers may be difficult to find and actuate using only the strength of human fingers, especially under emergency conditions. Moreover, many prior art latch systems may be subject to being inadvertently relocked under the human stress normally attendant to dealing with an emergency situation.